Referate. 283 



nämlich vom i. — 19. August. Aus dieser Einheitlichkeit des Materials er- 

 gibt sich nach Verf. wohl mit Recht die Regelmäßigkeit des Endresultates. 

 Verf. findet nämlich eine völlige Übereinstimmung seiner Zählungen mit 

 dem, was nach dem Ludwigschen Gipfelgesetze zu erwarten war. Seine 

 Haupt- und Nebengipfel fallen nämlich, soweit das Material als ganzes be- 

 trachtet wird, ausschließlich auf Haupt- oder Nebengipfel der Fibonacci- 

 reihe. Dazu ist der Hauptgipfel sehr hoch, die Nebengipfel aber sind 

 relativ niedrig. Die von verschiedenen Seiten bei ChrysaiitJiciiiiim Lcucan- 

 thcmum gefundenen Abweichungen von der Fibonaccireihe führt Verf. auf in 

 den betreffenden Untersuchungen benutztes unzureichendes Material zurück. 

 Ein Ansteigen des Mittelwertes bei zunehmender südlicher Breite, wie es 

 für Bctlis pcrcnitls von verschiedenen Seiten festgestellt wurde, ergab sich 

 nach Vergleichung mit früheren Untersuchungen anderer Autoren nicht. 



L. Lehmann. 



Punnett, R. C. Inheritance of Coat-Colour in Rabbits. Journal of Genetics 

 11 No 3, November 1912. 



This is an account of very complete experiments with several genetic 

 factors influencing the coat colour of rabbits. The paper confirms the 

 views of Castle and Hurst, and furthermore gives evidence of the 

 behaviour of three factors which have not hitherto been extensively studied 

 in rabbits. One of these factors is the one which distinguishes "Himalayan" 

 rabbits from ordinary albinos. Punnett found that nearly all his self- 

 coloured animals contained this factor, as matings of self-coloured rabbits 

 with Himalayans never gave ordinary albinos in Fo, but only Himalayans 

 (albinos with coloured extremities). I have recently shown that there are, 

 as was to be expected, self-coloured animals having this factor, and others 

 lacking it. Captn. Smits has kindly furnished me with data on matings 

 of chocolate rabbits with Himalayans, which matings gave ordinary and 

 Himalayan albinos in F.,. Punnett's work with chocolate rabbits con- 

 firmed my prediction that the relations of cinnamon, chocolate and orange 

 in rabbits are the same as in mice. As yet it seems that no one has 

 seriously worked with the factor which distinguishes black rabbits from 

 blue ones, and whose absence from chocolate, orange, agouti and other 

 colours produces corresponding "dilute" ones as in mice. Punnett's 

 "dilute" colours are those which are caused by the absence of the factor 

 which distinguishes black from tortoise, and chocolate from orange in 

 rabbits and mice. 



His factor E is therefore not to be confused with the other one, 

 which has as yet only been studied extensively in mice, and very little 

 in the cavy by myself. This to avoid confusion by the double meaning 

 of the term "Dilute". 



One of the most important points of this thoroughly readable paper 

 is the evidence for a coupling between two factors. The facts are these: 

 A is called the factor which makes the difference between black and 

 wildcoloured animals, the latter having it ; E is the factor which by its 

 presence turns yellow into wildcoloured, and tortoise into black. If a third 

 factor, D is present in an animal which, were D absent should be wild- 

 coloured, by the action of A on a black animal, this rabbit remains black, 

 D counteracts A. 



Now Punnett found that the DD EE AA animals are blacker than 

 the Dd EE AA ones, but that the Dd Ee AA ones are as black as the 



